in Twitter/SDK/Auth/OAuth1Helper.cs [183:204]
private string UrlEncode(IEnumerable<KeyValuePair<string, object>> parameters)
{
StringBuilder parameterString = new StringBuilder();
var paramsSorted = from p in parameters
orderby p.Key, p.Value
select p;
foreach (var item in paramsSorted)
{
if (item.Value is string)
{
if (parameterString.Length > 0)
{
parameterString.Append("&");
}
parameterString.Append($"{item.Key}={(string) item.Value}");
}
}
return WebUtility.UrlEncode(parameterString.ToString());
}